The art of oxygen evolution is an old one and is highly developed. Nickel has been and remains the preferred choice for alkaline electrolysis anodes because it has the best efficiency and corrosion resistance characteristics among the non-precious metals. It is known that during operation the nickel anode surface is converted completely to various nickel oxide and hydroxide species on which the oxygen is actively evolved. Researchers have determined that the chemical nature of the first few molecular layers of the oxide film is of major importance in determining the efficiency of the oxygen evolution reaction. Other researchers have found that the species beta-NiOOH is particularly active. The active nickel surface species is referred to herein as nickel oxyhydroxide.
The present invention is directed towards increasing the amount of nickel oxyhydroxide at the anode surface above that which would normally be formed directly by anodization of the nickel surface.